Version 1 of the sliver info extension

Provide information within the manifest about the sliver - for use with reporting to the GMOC.

To be added to manifests

geni_sliver_info is meant to extend the node or link element.

• creator_urn -- URN of the creator of the sliver
• creation_time -- time the sliver was created
• expiration_time -- time the sliver will expire
• start_time -- (optional) time when the sliver will actually be started (to cover the case when you schedule things for the future)
• state -- (optional) state of the sliver
• destroyed -- (optional) boolean indicating if the sliver has been deleted or otherwise removed
• error -- (optional) error string